Three new reader-only tests pin the .ail.json / .ailx bijection
plus AST-variant coverage. All three passed first observation
across the current corpus — no roundtrip, schema-coverage, or
CLI-drift gaps surfaced.
- every_ailx_fixture_matches_its_json_counterpart (replaces the
3-pair handwritten exhibits): 57 paired .ailx fixtures pass.
- every_ast_variant_is_observed_in_the_fixture_corpus (new): 34/34
AST variants exercised across 136 fixtures; exhaustive matches
without _ wildcard so AST drift fails the build.
- cli_render_then_parse_preserves_canonical_bytes_on_every_fixture
(new): 136 fixtures round-trip through ail render → tempfile →
ail parse with BLAKE3 identity on canonical bytes.
No production code, no DESIGN.md changes (those follow in later
iterations). Tests are pure readers of the repo per spec
acceptance #7 — tempfile crate added as workspace dep for the CLI
roundtrip's intermediate file outside the repo.